I would say follow a similar process to what ryan said but i would not recommend using rope.
How to strap mattress to roof rack.
After the mattress is secure in the plastic place the mattress on the roof.
Consider a roof rack.
Mattresses are large bulky and can pick up resistance from the wind.
If you have a roof rack the straps ropes can be looped around the side and cross rails.
Still there is a basic method to follow when tying a mattress to the roof of a car.
I came across a guy on the highway that only had a strap going across.
Stack items evenly across the roof and in the center of the doors.
On each side of the roof you ll see a rack that runs the length of the roof of the vehicle.
If you do put it on the roof of your vehicle have a strap run from front to back as well as from side to side.
A ratchet strap ensures that the mattress will not flay away while driving especially if you do not have a roof rack.
The second option is the side racks.
Lighter goes lower place heavier items on top of lighter items.
If you do secure your mattress to a roof rack or safely in the bed of a truck strap it down with ratcheting straps.
Put a piece of rope on the roof of the car that goes from back bumper to front bumper.
Learn how to safely secure items to your car s roof racks.
Cover the entire load with a tarp or netting to prevent things from falling out.
The mattress had lifted up in the front and ripped the roof racks right off.
Racv s ernest litera shares some practical tips on roof rack safety loading.
Ratcheting straps are much less likely to fail when moving a bulky item like a mattress.
Put the mattress on top of the car and rope so that it goes length wise with the length of the car see pics above.
With the third option crossbars with side rails you can secure an item to the side rails and run tie downs from front to back securing them to the crossbars.
Tie down the boards lengthwise and widthwise similar to how you d secure a mattress.
A simple ratchet strap works best.
Buy sturdy rope nylon or polyester based.
Pull the rope tight so there is no extra slack.
Once the rope is tightly placed on the mattress open all.
This will stress any knot no matter how securely tied.
Center the mattress in the middle and put the rope over the length of the mattress.
Make sure your ro.